Question

I’ve implemented the clickable table cell using a extended class. However, when I call the event handler/onclick method in my main class, the event handler doesn’t work.

Extended clickable table cell class:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace Member
{
    public class TableCellClick: TableCell, IPostBackEventHandler, INamingContainer
    {
        private static readonly object click_event = new object();

        // public handles for adding and removing functions to be called on the click event
        public event EventHandler Click
        {
            add
            {
                Events.AddHandler(click_event, value);
            }
            remove
            {
                Events.RemoveHandler(click_event, value);
            }
        }

        // define parent function that will be called when the container is clicked
        protected void OnClick(EventArgs e)
        {
            EventHandler h = Events[click_event] as EventHandler;
            if (h != null)
            {
                h(this, e);
            }
        }

        // specify the "post back event reference" or id of the click event
        protected override void AddAttributesToRender(HtmlTextWriter writer)
        {
            base.AddAttributesToRender(writer);
            writer.AddAttribute(HtmlTextWriterAttribute.Onclick, 
                                Page.ClientScript.GetPostBackEventReference(this, "custom_click"));
        }

        // link the custom click id to the click function
        void System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(string eventArgument)
        {
            if(eventArgument == "custom_click")
            {
                OnClick(EventArgs.Empty);
            }
        }
    }
}

The method in my Main class:

        memPanel.Visible = true;

        //Set a table width.
        memTable.Width = Unit.Percentage(40.00);
        //Create a new row for adding a table heading.
        TableRow tableHeading = new TableRow();

        //Create and add the cells that contain the msno column heading text.
        TableHeaderCell msnoHeading = new TableHeaderCell();
        msnoHeading.Text = "M'Ship No.";
        msnoHeading.HorizontalAlign = HorizontalAlign.Left;
        tableHeading.Cells.Add(msnoHeading);

        //Create and add the cells that contain the Name column heading text.
        TableHeaderCell nameHeading = new TableHeaderCell();
        nameHeading.Text = "Name";
        nameHeading.HorizontalAlign = HorizontalAlign.Left;
        tableHeading.Cells.Add(nameHeading);

        memTable.Rows.Add(tableHeading);

        while (reader.Read())
        {
            TableRow detailsRow = new TableRow();
            TableCellClick msnoCell = new TableCellClick();
            msnoCell.Text = reader["MSNo"].ToString();
            msnoCell.Click += cellClick;
            detailsRow.Cells.Add(msnoCell);

            TableCellClick nameCell = new TableCellClick();
            nameCell.Text = reader["fName"].ToString();
            nameCell.Click += cellClick;

            memTable.Rows.Add(detailsRow);

        }

The onclick method:

protected void cellClick(object sender, EventArgs e)
{
    System.Diagnostics.Debug.WriteLine("cell click");
    memPanel.Visible = false;
    basicInfo.Visible = true;
}

Anyone knows where it went wrong?

Answer 1

The reason why it wasn’t called is because of the postback method every time a button is clicked.
My cell wasn’t created in the pageload method that’s why it didn’t get called when the cell button is clicked.